Portable heaters and hand warmers are used as a source of heat. These heaters have fuel reservoirs, combustion chambers and means for conveying the fuel from the reservoirs to the combustion chambers. Similar structures are used in coal oil stoves and oil lamps. These structures are not adapted to be transported around in the trunks and tool boxes of motor vehicles. They are not connectable to conventional containers or cans, as each reservoir has special structure for accommodating the combustion chamber structure.